We study, both numerically and analytically, the development of equilibrium after preheating. We show that the process is characterized by the appearance of Kolmogorov spectra and the evolution towards thermal equilibrium follows self-similar dynamics. Simplified kinetic theory gives values for all characteristic exponents which are close to what is observed in lattice simulations. The resulting time for thermalization is long, and temperature at thermalization is low, T approximately 100 eV in the simple lambdaPhi(4) inflationary model. Our results allow a straightforward generalization to realistic models.
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http://dx.doi.org/10.1103/PhysRevLett.90.121301 | DOI Listing |
Rev Mod Plasma Phys
December 2024
Institut für Theoretische Physik, Technische Universität Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany.
The concept of electromotive field appears in various applications in space and astrophysical plasmas. A review is given on the electromotive field highlighting our current understanding of the theoretical picture and the spacecraft observations in interplanetary space. The electromotive field is a key concept to successfully close the set of turbulent magnetohydrodynamic equations and also to construct a more complete picture of space plasma turbulence.
View Article and Find Full Text PDFPhys Rev Lett
February 2024
Nordita, KTH Royal Institute of Technology and Stockholm University, 10691 Stockholm, Sweden.
In the standard model of particle physics, the chiral anomaly can occur in relativistic plasmas and plays a role in the early Universe, protoneutron stars, heavy-ion collisions, and quantum materials. It gives rise to a magnetic instability if the number densities of left- and right-handed electrically charged fermions are unequal. Using direct numerical simulations, we show this can result just from spatial fluctuations of the chemical potential, causing a chiral dynamo instability, magnetically driven turbulence, and ultimately a large-scale magnetic field through the magnetic α effect.
View Article and Find Full Text PDFPhys Rev Lett
December 2023
Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.
Transient electron dynamics near the interface of counterstreaming plasmas at the onset of a relativistic collisionless shock (RCS) is investigated using particle-in-cell simulations. We identify a slingshotlike injection process induced by the drifting electric field sustained by the flowing focus of backward-moving electrons, which is distinct from the well-known stochastic acceleration. The flowing focus signifies the plasma kinetic transition from a preturbulent laminar motion to a chaotic turbulence.
View Article and Find Full Text PDFPhys Rev Lett
July 2023
Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Am Mühlenberg, Potsdam-Golm 14476, Germany.
We perform a general-relativistic neutrino-radiation magnetohydrodynamic simulation of a one second-long binary neutron star merger on the Japanese supercomputer Fugaku using about 85 million CPU hours with 20 736 CPUs. We consider an asymmetric binary neutron star merger with masses of 1.2M_{⊙} and 1.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
July 2023
Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel.
Inertia-less viscoelastic channel flow displays a supercritical nonnormal mode elastic instability due to finite-size perturbations despite its linear stability. The nonnormal mode instability is determined mainly by a direct transition from laminar to chaotic flow, in contrast to normal mode bifurcation leading to a single fastest-growing mode. At higher velocities, transitions to elastic turbulence and further drag reduction flow regimes occur accompanied by elastic waves in three flow regimes.
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